Transformer



1,6351? July 12 1927 w. KUMMERER 94 TRANSFORIER Filed Aug. 1a. 1925 Patented- Julyiz, 1927. y UNITEDfSTTES( 1,635,194 A1?*.a11-:N'r OFFICE.

WILHELM'KUMMERE, 0F BERLIN, GERMANY, ASSIGNOR T0 GESELLSCHAFT EUR DRAHTLOSE TELEGRABAHIE M. B. HALLESCHES, OF BERLIN, GERMANY, A COR- PORATION F GERMANY.

TRANSFORM'ER.

Application Aillexl August 18i,1925,'8eria1 No. 50,981, and in Germany September 9,1924;

rMy invention relates to a device for converting alternating current of one potential toalterna'tin current of the sameA ordifferent potential, known'in the 'art as trans- 5 'formera i f My invention relatesmore particularl to a transformer whichl must withstand a igh direct current potential between primary and secondary windings.

An object of the invention is to provide a transformer of the above described kind 'which will not break down on high direct current voltage, will not' unduly heat up, 1' and yet willbe cheap 'to manufacture, take 16 up but a small space and be efhcient in use. lOther objects will be. apparent from the following descri tion and appended claims when considere with the accompanying drawing which represents an embodiment of 20 my invention.

In using rectifiers comprising an incandescent cathode as, for instane, a highvacuum rectifier, or a Wehnelt "rectifier, in the case of connections of the kind employed with electron discharge tube "transmitters, it has been found that the heatedl filaments of the rectifiers possess the full direct current potential to ground. In the case of rectifiers worked with high direct current potentials as, for instance, of the-order of 10,000 volts, it is therefore' necessary that a transformer for a comparativel small en` ergy' must be provided with su cientinsulation, however, between primary and secondary to withstand v10,000 volts, while the alternating current voltage in the secondary 4winding ranges 'mostly only between 10 and y20volts.

The usual form of construction of trans- 40 formers with-a solidinsulatorbetween pril mary and secondary windin 'as presspahn, micanite, Ietc., therefore lea sto vfrequent breakdowns, since the insulation ,material is subject to slow destructionunder the action,

ofthe direct current potential due toelec trolytic effects. The danger existing for transformers is intensified owing to the fact that in transmittersf\,more or less high fre- `pllency potentials arise frequently Ybetweenl t e primary and the secondary winding, and the dielectric` Vlosses caused thereby result in marked y heating of the insulation. i Another point is that ovevoltages cannot be completel?7 precluded under practical working -con itions.

y consequence, resultin Now the subject matter ofthe present invention consists of a transformer which is constructed toA withstand the said stresses, while it is subject to little stray, and is of small dimensions. The essential feature of .thenew arrangement resides in that between the windings, `no solid insulation is rovided, and also in that the secondaryrwind- -ing carrying high potential direct currents 1s carried'by high voltage insulators which can be made o f a material .which is not `hygroscopic or heat-sensitive. A particularly important point in this arrangement is that 'the primary winding is screened or shielded by the' aid of a sheet metal cylinder,

My invention is illustrated in the accomp anying drawing which shows a side elevation, partly in section, of my new improved transformer.

Referring now more particularly to the drawing, 1 is the iron core on which is placed an insulating cylinder 2 which carries the prnnary winding 3. The said primary winding is brought. out to the two terminals 4 land '5. The secondary winding which is denoted by 6 is wrapped-on a cylindrical bobbin or coil tube 7 made of metal. Tube 7 is ,SUPPOrted solely by the high tension insulators 8 and 9 by means of rod 26. k,Insulators 8 and 9 rest upon the magnetic core 1. The secondary winding 6 is therefore arranged to freely surround the primary winding 3 without'any other dielectricthan air being employed for insulating purposes. The endsA of the secondary winding 6 are brought out to terminals 24 and 25. y Placed directly over the prima winding 3 is the sheet metal cylinder 10 which is conductively connected with a convenient point of the primary winding. Another Aessential point is that the metallic tube 7. of-the high tension winding 6 is in single point connection with the secondary winding 6. As a from the cylindrical construction of the co11s,` there is obtained an entirely uniform direct. current electrostatic field betweentubes Z and 10. Hence, a rela- ,tively small distance between the two tubes will' suflice in this arrangement.

If the sheet metall tubelO were omitted, 105 irregularities in the Vsmooth/ness ofthe windi ing 3 might result-in a breakdown even .at muchv lower potential differences. In addition, the arrangement offers this further vsubstantial advantage that the transformer in 11 the case of excess yvoltage flashes over between the metallic tubes 7 and 10 withoutcausing damage to the winding of the 'trans-` former as a consequence.: To avoid` eddy currents, the metal tubes 7 andb 10 are split, as indicatedat'2l and 22.

It goes without saying that the. entire i transformer, for the purpose of more eiii-v cient cooling, and to increase-the punctura' bility, may bebimniersediin oil or any other desirable cooling liquid in..` Well known manner. 1

Having .described my invention, I amentitled to all modifications thereof as fall fairly within its\s irit andgscope,.as delined'p by the following c aims v l. A transformer comprising, a magnetic circuit, a tube of ,insulation surrounding a portion of said circuit, a first winding sur- ?rounding said tube of insulation,l a first metal tube surrounding said first winding,

` post insulators resting upon said circuit, a

second metal tube supported'by said -insulators, said second metal tube surrounding and being in spaced relation to said first Winding, and a second winding surrounding said second metal tube, said metal tubes being split longitudinali 2. A transformer comprising, a magnetic -icircuit, a irst winding surrounding a portion of said circuit, a first metal `tubesurrounding and connected to `a` point of said rst winding, post insulators resting upon sald circuit, and a second winding supported rent potentials, in which under normal workinU conditions there exists a high potential /dierence between the primary and secondary windings. comprising 'a low tension winding, a high tension Winding` a cylindrical metal body adapted to support said high tension winding and insulators supporting said body in spaced relation to said low tension winding.

.5. The transformer according 'to claim 4,

including a spdit sheet metal cylinder adapted to screen the 'low potential winding and in conduct-ive connection therewith.

' YWILHELM KUMMEBER. 

